Uremia

Uremia or uraemia (see spelling differences) is a term used to loosely describe the illness accompanying kidney failure

Renal failure

Renal failure or kidney failure is a situation in which the kidneys fail to function adequately. It is divided into acute and chronic forms; either form may be due to a large number of other medical problems....

 (also called renal failure), in particular the nitrogenous waste products associated with the failure of this organ.

In kidney failure, urea

Urea

Urea or carbamide is an organic compound with the chemical formula ₂CO. The molecule has two amine residues joined by a carbonyl functional group....

 and other waste products, which are normally excreted into the urine

Urine

Urine is a liquid waste product of the body secreted by the kidneys by a process of filtration from blood called urination and excreted through the urethra. Cellular metabolism generates numerous waste compounds, many rich in nitrogen, that require elimination from the bloodstream...

, are retained in the blood. Early symptoms include anorexia and lethargy, and late symptoms can include decreased mental acuity and coma. It is usually diagnosed in kidney dialysis patients when the glomerular filtration rate, a measure of kidney function, is below 50% of normal.

Azotemia

Azotemia

Azotemia is a medical condition characterized by abnormal levels of nitrogen-containing compounds, such as urea, creatinine, various body waste compounds, and other nitrogen-rich compounds in the blood...

is another word that refers to high levels of urea, but is used primarily when the abnormality can be measured chemically but is not yet so severe as to produce symptoms. Uremia can also result in fibrinous pericarditis. There are many dysfunctions caused by uremia affecting many systems of the body, such as blood (lower levels of erythropoietin), sex (lower levels of testosterone/estrogen) and bones (osteoporosis and metastatic calcifications).

Causes

Besides renal failure

Renal failure

Renal failure or kidney failure is a situation in which the kidneys fail to function adequately. It is divided into acute and chronic forms; either form may be due to a large number of other medical problems....

, the level of urea in the blood can also be increased by:

• increased production of urea in the liver, due to:
  • high protein diet
  • increased protein breakdown (surgery, infection, trauma, cancer)
  • gastrointestinal bleeding
  • drugs (e.g. tetracyclines and corticosteroids)

• decreased elimination of urea, due to:
  • decreased blood flow through kidney (e.g. hypotension
    Hypotension
    In physiology and medicine, hypotension refers to an abnormally low blood pressure. This is best understood as a physiologic state, rather than a disease. It is often associated with shock, though not necessarily indicative of it. Hypotension is the opposite of hypertension, which is high blood...
    
    , cardiac failure)
  • urinary outflow obstruction

• dehydration
• chronic infection of the kidney such as chronic pyelonephritis
  Pyelonephritis
  Pyelonephritis is an ascending urinary tract infection that has reached the pyelum of the kidney . If the infection is severe, the term "urosepsis" is used interchangeably . It requires antibiotics as therapy, and treatment of any underlying causes to prevent recurrence...